Bullet Penetration

This is a discussion on Bullet Penetration within the Defensive Ammunition & Ballistics forums, part of the Defensive Carry Discussions category; Two weeks ago I ordered Bullet Penetration by Duncan MacPherson. I have read this interesting book two times. This book stresses the importance of having ...

Bullet Penetration

Two weeks ago I ordered Bullet Penetration by Duncan MacPherson. I have read this interesting book two times. This book stresses the importance of having penetration in the area of 13 to 16 inches. Duncan claims that when using the heaviest weight in each caliber (depending on type & brand of ammo) you should achieve this desired penetration. Duncan claims that some situations you may need more then the FBI recommended 12 inches of penetration--so if you choose ammo that penetrates say 14 inches and you have to shoot through an arm to get a vital organ shot that you will at least get the minimum of 12 inches. Duncan also claims that a longer permanent wound channel creates more tissue damage.

Do any shooters have any comments on this information by Duncan MacPherson?
I'm starting to wonder if I'm taking his book too seriously --any thoughts on this information?

I carry 147grain 9mm. I like the heavier rounds. There are really just too many variables in trying to guess whats going to happen. Pick yourself a good round, HST, Gold Dot, Ranger, Golden Saber, DPX and your good to go. Hopefully you will never have to use them. Practice, practice and shot placement and practice is more important. You have to get those expensive rounds on the target to make it matter. good luck

Penetration is not everything; a .223 FMJ has a lot of penetration; is it effective to stop a threat ? Not really.
What makes a human or animal stop is when he lost so much blood that the BP crashes and the CNS shuts down, unless you have a "lucky" hit; that's how people die instantly from a .22 LR shot.
Otherwise, the bigger the holes, the faster the blood loss.

The carry gun has to be a compromise; ideally, I would like to be able to shoot 12 ga. slugs from my P3-AT , but I can't; I'd like to carry my .44 mag 8" barrel Blackhawk with Silhouette loads, but it is too heavy, bulky, etc.

So I compromise on a 9mm Glock with Speer GD because IMO it is a good compromise, not saying the best.
In the last 30 years, I drew my gun twice, and didn't have to shoot.
So I am not going to loose any sleep on figuring if this ammo has 14% more penetration but 12% less expansion than that ammo.
I train for 2 things:
- avoidance, deterrence, de-escalation.
-combat accuracy at close range under stress.
You can never cover anything 100%, it is human.

"silver" says it right. Any of the top ammo will do the job. Personally, I use Corbon DPX in my 9mm and .40 S&W carry pieces. Penetration tests are done in ballistics gel, which approximates flesh. You start having to go through bone and heavy clothing and that's where you'll want the extra penetration some rounds give. Whatever round causes the most internal damage is the one you want.

At the end of the day, like silver said, and keltyke agrees with... you have to hit what you are shooting at. No hole is a good hole, that being said, after all is said and done, after you have hit your intended target, a bigger/deeper hole will do more damage, causing more blood loss, stopping BG.

"You will not rise to the occasion and you will not default to your level of training. You WILL ONLY default to the level of training you have mastered."
-Ruger P345; LCP
-Mossberg 590A1; Model 42
-Phoenix Arms Raven

One of my instructors hinted about the penetration ordeal. Once the 10mm round came about, the penetration issues went out the window....previous schools of thought wanted the bullet to penetrate deeply enough and induce the most shock in it's wake while not exiting. The 10mm theory says go in, go through, and cause a larger hole on exit for more blood loss. To this day I still don't have a 10mm pistol, but it all makes sense in a way. I tend to believe more in my abilities than any other scientific notion that wants to tell me what I need and how much I need of it in order to reach my goal. You simply do the best with what tools you've taken out of the toolbox to do the task at hand. The only times you'll come up on the short end of the stick is when you either don't choose the right tool for the job, or you don't know the task at hand. Some folks like to carry a few tools in their back pocket to do most jobs....others carry a full tool bag that's rather heavy, but has everything they need to accomplish tasks. Carrying a bag with multiple tools is a heavier burden than just three tools in the back pocket. Carrying an adjustable wrench might work for a lot of things, but sooner or later, you'll bust your knuckles with it and bleed. If you bleed on the job, you'll end up being tested for drugs before they even attempt to stitch you up. So...the best thing to do in my opinion, is to have a full tool bag at your disposal when you go to work on solving a problem. It's going to go a lot easier on you in the long run. Work smarter, not harder is my motto. Sometimes we all over-think things, and hence we make it harder on ourselves, and take longer to complete the task at hand. The only thing in this world you can ultimately depend on is you and your own decisions. Everything else either helps you make those decisions, or they bog you down with questions and indecisiveness. Questions take up way too much time in my opinion. Focus on the task at hand and have available the tools necessary to keep yourself from bleeding.

Well, in the example scenarios given in the OP more penetration would certainly be good. There are pros and cons either way when talking heavier and deeper versus light, shallower and faster. You'll have to decide what is appropriate for you based on the situations you are most likely to encounter. The whole winter/summer thing that those up north face is probably the example I see most often.

Well, you don't have to work too hard to also come up scenarios where over-penetration is a bad thing. There's the whole "wasted energy" angle - the wasted energy pushing that heavier, slower bullet out of the target and beyond...into what?

I mean seriously, in 9mm for example, 115 gr. vs. 124 gr. vs. 147 gr.: if you put it into/through a major blood-bearing organ (and aren't they all?) - there's no measurable difference.

What about recoil? Often heavier bullets have noticeably stouter recoil, thus reducing the accuracy of follow-up shots.

Exit wounds? You can still bleed out internally, even if the bullet doesn't exit. In some ways, speaking in terms of first aid or ER care, having no exit wound is a lot worse (for the woundee and the attending physicians) than having an exit wound (and hence a fairly clearly indicated bullet path through the body).

There is no guarantee, when hitting a BG in the arm with any handgun bullet, or rifle bullet for that matter, that it will continue on to penetrate the chest cavity and the heart.

So it really hasn't changed, FBI penetration paranoia notwithstanding. It's personal preference, bullet placement under extreme stress, what you can hit with, and what your gun will feed and shoot the best.

Personally, I would rather take accept the POSSIBILITY of overpentration than the PROBABILITY of underpenetration. Someone please correct me on this: I do not know of a single case where someone was killed by an overpenetrating hollow point pistol/revolver round after it has passed through a BG. People using the spray and pray method of gunfighting are much more dangerous to bystanders!
The deeper the wound channel, the greater the volume and the greater the incapacitation potential. Birdshot makes a horrible surface wound but ask Dick Cheney about it's stopping power.
Expansion is nice but penetration is mandatory.

The penetration point is a good one.. but one aspect that is usually not considered is the dangers of over penetration.
If you ever have to draw in public, chances are you will not have a safe back stop or even have the chance to think about that. You have to think about the possibility of incidental bullet strikes if your bullet goes through and through.
Scenario: You are at public event and Bad guy starts shooting. People are being shot. You have the opportunity to draw and put the BG down. You do so, perfect shot to chest. Bad guy falls and it is a great day until you realize your bullet also hit young child that was 20 yards behind said BG.
There is a reason to limit your penetration... to not accidentally hit someone other than your target.
In the event that you have to draw in a real scenario you will not have the opportunity to check the back drop... make your choice on this in your ammo purchase. Over-penetration could kill an innocent bystander.

...and you'll probably go to jail, and be completely financially ruined by the time the innocent bystander's family is done bleeding you dry. Those "under-penetrating" speer gold dot 124 +p's work pretty well for nypd.

I've always prefered heavier bullets in most larger non-magnum calibers. Not so much with 9mm and .357 magnum. Considering the likelyhood of where a defensive shooting would most likely occur for me and over-penetration is a huge factor.
I remember when 147gr. 9mm loadings started to become popular. The 2 biggest problems were over-penetration in soft tissue because of a lack of expansion and under-penetration of hard objects because of a lack of energy. The newer loadings have tackled those issues a bit with better bullet designs and +P velocities but now you have loads that perform similar to 115 and 124 grain loads but have a significantly different POA/POI at any reasonably extended ranges. Considering that probably 99% of my practice is with 115 grain fmj, that's a deal breaker for me. I still have concerns about soft tissue over-penetration, founded or not.
In .357, the Remmy & Fed. 125 jhps have been working wonderfully for decades without substantial over-penetration issues. No reason to change there.